Torque converter with deflectable seal

ABSTRACT

A torque converter assembly comprises: a cover for driving engagement with a prime mover; a piston plate including an annular surface for engaging a clutch; and, a sealing plate comprising a substantially radial wall arranged between the cover and the piston plate and disposed radially inward of the annular surface, wherein: in a lockup mode for the torque converter, the sealing plate blocks fluid flow between the cover and the piston plate; and, in a release mode for the torque converter, the sealing plate is deflectable to enable a fluid flow between the cover and the piston plate via a pathway between the cover and the sealing plate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of application Ser. No. 13/173,813,filed on Jun. 30, 2011, which claims the benefit of U.S. ProvisionalApplication No. 61/360,382 filed on Jun. 30, 2010, which applicationsare incorporated herein by reference.

FIELD

The invention relates generally to a torque converter, and morespecifically to a torque converter with a deflectable seal.

BACKGROUND

Torque converters with seals are known. One example is shown in GermanPatent Application Publication DE 10 2008 048 031 A1.

BRIEF SUMMARY

Example aspects broadly comprise a torque converter assembly including acover for driving engagement with a prime mover, a piston plateincluding an annular surface for engaging a clutch, and a first sealdisposed radially inward of the annular surface. In a lockup mode forthe torque converter, the first seal blocks fluid flow through anorifice in the piston plate or between the cover and the piston plateand, in a release mode for the torque converter, the first seal isdeflectable to enable a fluid flow through the orifice or between thecover and the piston plate and around the first seal. In an exampleembodiment, the torque converter assembly includes an apply chamber, thepiston plate is displaceable in response to fluid pressure in the applychamber, and the first seal is arranged to be deflected by the fluidpressure in the apply chamber.

In some example embodiments, the torque converter assembly includes asheet metal plate fixed to the piston plate. In some exampleembodiments, the first seal is fixed to the sheet metal plate andarranged for sealing engagement with the cover. In an exampleembodiment, the first seal includes a flap portion deflectable to blockthe fluid flow between the cover and the piston plate, or through thepiston plate orifice, or, enable the fluid flow between the cover andthe piston plate, or through the piston plate orifice.

In some example embodiments, the first seal includes a sheet metal ringfixed to one of the piston plate or the cover and arranged for sealingengagement with the other of the piston plate or the cover when thetorque converter is in the lockup mode. In an example embodiment, duringthe lockup mode, the sheet metal ring is in contact with the other ofthe piston plate or the cover. In an example embodiment, the first sealhas a sealing portion including rubber or friction material bonded tothe sheet metal ring and, during the lockup mode, the sealing portion isin contact with the other of the piston plate or the cover.

In some example embodiments, the first seal includes a sheet metal plateand friction material bonded to the sheet metal plate. In the lockupmode, the friction material blocks the fluid flow through the pistonplate orifice and, in the release mode, the friction material isdisplaceable to enable the fluid flow through the piston plate orifice.In some example embodiments, the torque converter includes a second sealassembly having a seal plate fixed to the piston plate and a second sealsealingly engaged with the cover. In an example embodiment, the sealplate includes an annular groove and the second seal is disposed in thegroove. In an example embodiment, the seal plate includes a portion ofan annular groove, the piston plate includes a portion of the annulargroove, and the second seal is disposed in the groove.

Other example aspects broadly comprise a torque converter assemblyincluding a cover for driving connection to a prime mover, an impellerdrivingly connected to the cover, a piston plate, first and secondchambers, and a deflectable seal fixed to one of the cover or the pistonplate. The first chamber is at least partially defined by the cover andthe piston plate and the second chamber is at least partially defined bythe cover, the impeller, and the piston plate. In a first position, thedeflectable seal is disengaged from the other of the cover or the pistonplate to enable a flow around the seal from the first chamber to thesecond chamber. In a second position, the deflectable seal is engagedwith the other of the cover or the piston plate to block a flow from thesecond chamber to the first chamber.

In an example embodiment, the torque converter assembly includes a sheetmetal plate fixed to the piston plate. The deflectable seal is fixed tothe sheet metal plate, arranged for sealing engagement with the cover,and includes a flap portion. The flap portion is deflectable to enablethe flow from the first chamber to the second chamber or block the flowfrom the second chamber to the first chamber. In some exampleembodiments, the deflectable seal includes a sheet metal ring fixed toone of the piston plate or the cover and arranged for sealing engagementwith the other of the piston plate or the cover to block the flow fromthe second chamber to the first chamber. In an example embodiment, thedeflectable seal includes a sealing portion bonded to the sheet metalring and contactable with the other of the piston plate or the cover toblock the flow from the second chamber to the first chamber.

In some example embodiments, the torque converter assembly includes asecond seal assembly having a seal plate fixed to the piston plate and asecond seal sealingly engaged with the cover to block the flow betweenthe chambers. In an example embodiment, the seal plate includes anannular groove and the second seal is disposed in the groove. In anexample embodiment, the seal plate includes a portion of an annulargroove, the piston plate includes a portion of the annular groove, andthe second seal is disposed in the groove.

Other example aspects broadly comprise a torque converter assemblyincluding a cover for driving connection to a prime mover, a pistonplate, and a seal disposed between the cover and the piston plate, fixedto one of the cover or the piston plate, and including an orifice and/orat least one radial slot. In a first position, the seal is disengagedfrom the other of the cover or the piston plate to enable a flow aroundthe seal between the cover and the piston plate. In a second position,the seal is engaged with the other of the cover or the piston plate toblock the flow between the cover and the piston plate with the exceptionof a flow through the orifice and/or the at least one radial slot.

BRIEF DESCRIPTION OF THE DRAWINGS

The nature and mode of operation of the present invention will now bemore fully described in the following detailed description of theinvention taken with the accompanying drawing figures, in which:

FIG. 1A is a perspective view of a cylindrical coordinate systemdemonstrating spatial terminology used in the present application;

FIG. 1B is a perspective view of an object in the cylindrical coordinatesystem of FIG. 1A demonstrating spatial terminology used in the presentapplication;

FIG. 2 is a top half cross-sectional view of a prior art torqueconverter;

FIG. 3A is a schematic view of the torque converter of FIG. 2 with adeflectable sealing plate shown in an apply state, according to anexample aspect;

FIG. 3B is a schematic view of the torque converter of FIG. 2 with adeflectable sealing plate, shown in a release state, according to anexample aspect;

FIG. 3C is a section view of a sealing plate shown with a zig-zag shape;

FIG. 3D is a section view of a sealing plate shown with circular sealingelement 206;

FIG. 4A is a schematic view of the torque converter of FIG. 2 with adeflectable sealing plate shown in an apply state, according to anexample aspect;

FIG. 4B is a schematic view of the torque converter of FIG. 2 with adeflectable sealing plate, shown in a release state, according to anexample aspect;

FIG. 4C is a back view of the seal shown in FIG. 4B;

FIG. 5 is a top half cross-sectional view of a portion of a clutchassembly with a deflectable seal, according to an example aspect;

FIG. 6 is a top half cross-sectional view of a portion of a clutchassembly with a deflectable seal, according to an example aspect;

FIG. 7 is a top half-cross sectional view of a portion of a clutchassembly with a deflectable seal, according to an example aspect;

FIG. 8 is a top half cross-sectional view of a torque converter with aclutch assembly having a deflectable seal, according to an exampleaspect;

FIG. 9A is a front view the seal of FIG. 8;

FIG. 9B is a front view of an alternative embodiment of the seal of FIG.8;

FIG. 10 is a cross-sectional view of a portion of a clutch assembly,according to an example aspect;

FIG. 11 is a cross-sectional view of a portion of a clutch assembly,according to an example aspect.

DETAILED DESCRIPTION

At the outset, it should be appreciated that like drawing numbersappearing in different drawing views identify identical, or functionallysimilar, structural elements. Furthermore, it is understood that thisinvention is not limited only to the particular embodiments,methodology, materials and modifications described herein, and as suchmay, of course, vary. It is also understood that the terminology usedherein is for the purpose of describing particular aspects only, and isnot intended to limit the scope of the present invention, which islimited only by the appended claims.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood to one of ordinary skill inthe art to which this invention belongs. Although any methods, devicesor materials similar or equivalent to those described herein can be usedin the practice or testing of the invention, the following examplemethods, devices, and materials are now described.

FIG. 1A is a perspective view of cylindrical coordinate system 80demonstrating spatial terminology used in the present application. Thepresent invention is at least partially described within the context ofa cylindrical coordinate system. System 80 has a longitudinal axis 81,used as the reference for the directional and spatial terms that follow.The adjectives “axial,” “radial,” and “circumferential” are with respectto an orientation parallel to axis 81, radius 82 (which is orthogonal toaxis 81), and circumference 83, respectively. The adjectives “axial,”“radial” and “circumferential” also are regarding orientation parallelto respective planes. To clarify the disposition of the various planes,objects 84, 85, and 86 are used. Surface 87 of object 84 forms an axialplane. That is, axis 81 forms a line along the surface. Surface 88 ofobject 85 forms a radial plane. That is, radius 82 forms a line alongthe surface. Surface 89 of object 86 forms a circumferential plane. Thatis, circumference 83 forms a line along the surface. As a furtherexample, axial movement or disposition is parallel to axis 81, radialmovement or disposition is parallel to radius 82, and circumferentialmovement or disposition is parallel to circumference 83. Rotation iswith respect to axis 81.

The adverbs “axially,” “radially,” and “circumferentially” are withrespect to an orientation parallel to axis 81, radius 82, orcircumference 83, respectively. The adverbs “axially,” “radially,” and“circumferentially” also are regarding orientation parallel torespective planes.

FIG. 1B is a perspective view of object 90 in cylindrical coordinatesystem 80 of FIG. 1A demonstrating spatial terminology used in thepresent application. Cylindrical object 90 is representative of acylindrical object in a cylindrical coordinate system and is notintended to limit the present invention in any manner. Object 90includes axial surface 91, radial surface 92, and circumferentialsurface 93. Surface 91 is part of an axial plane, surface 92 is part ofa radial plane, and surface 93 is part of a circumferential plane.

The following description is made with reference to FIG. 2. FIG. 2 is atop half cross-sectional view of prior art torque converter 100. Torqueconverter 100 includes impeller assembly 102 with blades 104, shell 106,core ring 108 and impeller hub 110. Hub 110 is fixed to shell 106 byweld 112. Hub 110 is for sealing to a transmission (not shown) anddrivingly engaging a transmission pump (not shown). Converter 100further includes turbine assembly 114 with blades 116, shell 118, andcore ring 120.

Stator assembly 122 is axially disposed between impeller assembly 102and turbine assembly 114. Assembly 122 includes housing 124, one-wayclutch 126, and side plate 128. Clutch 126 may be a roller or spragdesign as is commonly known in the art. Thrust bearings 130 and 132 aredisposed on opposite axial sides of stator assembly 122.

Converter 100 includes cover assembly 134 fixedly attached to impellerassembly 102 at weld 136. Cover 134 includes shell 138, drive plate 140with lugs 142, and drive plate 144. Plates 140 and 144 are attached toshell 138 at respective rivets 146 and 148. One or both of rivets 146and 148 may be extruded rivets as is commonly known in the art.

Damper assembly 150 is disposed within converter 100. Assembly 150includes cover plates 152 and 154, flange 156, and elastic elements 158and 160. Elements 158 and 160 are in driving engagement with plates 152and 154, and flange 156. That is, elements 158 and 160 transmit torquefrom plates 152 and 154 to flange 156. Elements 158 and 160 may be coilsprings, for example. Plate 154 is attached to shell 118 and thrustplate 156 by rivet 158. Flange 156 is drivingly engaged with damper hub160 at spline 162. Bearing 164 is disposed axially between hub 160 anddrive plate 144, and radially positioned by axial extension 166 of plate144.

Clutch assembly 168 transmits torque from cover 134 to damper 150.Clutch 168 includes piston plate 170 and clutch plate 172. Piston plate170 may be an annular plate. Piston plate 170 is drivingly engaged todrive plate 144 by leaf springs 174 and rivet 176. Piston plate 170 issealed to damper hub 160 with dynamic seal 180. Clutch plate 172 isaxially disposed between piston plate 170 and cover 134. Plate 172includes friction material rings 186 and 188 disposed on axiallyopposite sides of plate 172. Plate 172 further includes tabs 190 forengaging complementary tabs 192 and 194 in respective cover plates 172and 174.

Piston plate 170 and damper hub 160 separate chambers 196 and 198 oftorque converter 100. Chamber 196 may be referred to as an apply chamberand is at least partially defined by impeller 102, cover 134, and pistonplate 170. Chamber 198 may be referred to as a release chamber and is atleast partially defined by cover 134 and piston plate 170. Clutchassembly 168 is engaged and disengaged by fluid pressure acting onpiston plate 170. Fluid pressure in apply chamber 196 urges piston plate170 towards engagement with cover 134, while fluid pressure in chamber198 urges piston plate 170 away from engagement with cover 134. Fluidenters chambers 196 and 198 through a transmission input shaft (notshown).

In order to change from a clutch release state to a clutch apply state,pressure in chambers 196 and 198 is reversed. That is, torque converter100 has a higher pressure in chamber 198 when clutch 168 is in releasemode. In order to engage clutch 168, pressure in chamber 196 must behigher than pressure in chamber 198. Therefore, pressure in chamber 196is raised and/or pressure in chamber 198 is lowered to engage clutch168. Even through pressure in chamber 196 may be higher, leakage betweenpiston plate 170 and clutch plate 172 may equalize pressure in chambers196 and 198 while the clutch is being engaged. That is, piston plate 170seals to friction material 188 when clutch 168 is applied, but allowsleakage before the two components are sealed. Leakage between piston 170and friction material 188 may make it difficult to build pressure inchamber 196 to fully engage clutch 168.

Furthermore, hydrodynamic effects in the torque converter affectengagement of clutch 168. For example, hydrodynamic effects urge pistonplate 170 in the direction of the faster-spinning component. Therefore,since piston plate 170 is axially disposed between cover 134 and damper150, piston plate will be urged towards cover 134 when impeller 102spins faster than turbine 114 (drive mode) and away from cover 134 whenturbine 114 spins faster than impeller 102 (coast mode). Otherwisestated, piston plate 170 tends to be self-engaging in drive mode andself-disengaging in coast mode. Therefore, it may be difficult to engageclutch 168 when converter 100 is in coast mode because fluid pressure inchamber 196 leaks into chamber 198 through the axial gap between piston170 and clutch plate 172. It should be noted that, although FIG. 2 showsthe gap between piston 170 and plate 172, the gap may be between covershell 138 and plate 172, or a portion of the gap may be between eachpair.

The following description is made with reference to FIGS. 3A-3D. FIG. 3Ais a schematic view of torque converter 100 of FIG. 2 with deflectablesealing plate 200 shown in an apply state, according to an exampleaspect. FIG. 3B is a schematic view of torque converter 100 of FIG. 2with deflectable sealing plate 200, shown in a release state, accordingto an example aspect. FIG. 3C is a section view of sealing plate 200shown with a zig-zag shape. FIG. 3D is a section view of sealing plate200 shown with circular sealing element 206. Converter 100 includescover 138 and piston plate 170 as described supra. In the embodimentshown in FIGS. 3A-3D, converter 100 includes deflectable sealing plate200.

Plate 200 is disposed axially between cover 138 and annular piston plate170, and is fixedly attached to piston 170 at attachment point 202.Plate 200 may be attached to piston 170 with rivets or welding, forexample. Plate 200 is arranged to seal to cover 138 at sealing portion204 to minimize fluid exchange between chambers 196 and 198. Althoughplate 200 is shown attached to piston plate 170, other configurationsexist and should be considered within the scope. For example, plate 200may be fixed to cover 138 and arranged to seal to piston 170. Therefore,as can be seen in FIG. 3A, pressure from chamber 196 leaking betweencover shell 138 and piston 170 is restricted from entering chamber 198,improving engagement of clutch assembly 168.

Converter 100 requires significant cooling flow during release mode.Cooling flow enters chamber 198 from the input shaft (not shown) andexits to from port 196. In the configuration shown in FIG. 3A, seal 200blocks flow between the chambers so the cooling flow may be insufficientand converter 100 may overheat. However, as can be seen in FIG. 3B, seal200 is deflectable to allow flow between the chambers when pressure ishigher in chamber 198. That is, pressure in chamber 198 urges seal 200away from shell 138 allowing flow between the chambers to cool converter100.

As described supra, piston 170 and cover shell 138 rotate together.Therefore, deflectable seal 200 may be a metal plate without risk ofwear or grinding between seal 200 and shell 138 because there is norelative rotation. Seal 200 may include a seal material (not shown) atportion 204 to improve sealing between plate 200 and shell 138. Forexample, seal 200 may include friction material at portion 204. Seal 200may include additional bends and radial walls between portions 202 and204 for increased flexibility. For example, seal 200 may have a“zig-zag” form as shown in FIG. 3C. Seal 200 may include ring 206 with acircular cross-section installed over portion 204 as shown in FIG. 3D.

The following description is made with reference to FIGS. 4A-4C. FIG. 4Ais a schematic view of torque converter 100 of FIG. 2 with deflectablesealing plate 200A shown in an apply state, according to an exampleaspect. FIG. 4B is a schematic view of torque converter 100 of FIG. 2with deflectable sealing plate 200A, shown in a release state, accordingto an example aspect. FIG. 4C is a back view of seal 200A. Plate 200A issealed to piston 170 with extruded rivet 208. In general, plates 200 and200A perform the same function. However, plate 200 seals against aradial wall of shell 138 while plate 200A seals against a conical wallof shell 138. As shown in FIG. 4C, seal 200A is a metal ring with radialtabs 210 having apertures 212 for receiving rivets 208. Ring 200A mayalso include radial slots 214 for increased flexibility. Operation ofseal 200A is as described for seal 200.

The following description is made with reference to FIGS. 5-7. FIG. 5 isa top half cross-sectional view of a portion of clutch assembly 300 withdeflectable seal 302, according to an example aspect. Seal 302 includesportion 304 fixed to piston plate 306 by riveting, for example, andportion 308 fixed to portion 304. Portion 308 may be a rubber sealportion bonded to portion 304. In general, seal 302 seals piston plate306 to cover shell 310 in clutch apply mode and deflects in clutchrelease mode similar to seal 200 described above. Seal 302 may includeorifice 312. Orifice 312 prevents pressure buildup between clutch plate314 and seal 302 during clutch apply. That is, any pressure trapped inchamber 316 during clutch apply drains into chamber 318 to improveclutch engagement. Although orifice 312 is shown in portion 308, otherembodiments may include orifice 312 in portion 304.

FIG. 6 is a top half cross-sectional view of a portion of clutchassembly 400 with deflectable seal 402, according to an example aspect.Seal 402 includes portion 404 fixed to piston plate 406 by riveting, forexample, and portion 408 fixed to portion 404. Portion 408 may be arubber seal portion bonded to portion 404. In general, seal 402 sealspiston plate 406 to cover shell 410 in clutch apply mode and deflects inclutch release mode similar to seal 200 described above. Cover 410includes circumferential wall 412 in sealing engagement with seal 402.Wall 412 is a coined, or stamped, feature of shell 410 and is integralwith shell 410. In other embodiments (described infra), wall 412 is aportion of an additional element fixedly attached to shell 410.

FIG. 7 is a top half-cross sectional view of a portion of clutchassembly 500 with deflectable seal 502, according to an example aspect.Seal 502 includes portion 504 fixed to piston plate 506 by riveting, forexample, and portion 508 fixed to portion 504. Portion 508 may be arubber seal portion bonded to portion 504. Portion 508 includes flap 509for deflecting. In general, seal 502 seals piston plate 506 to coverassembly 510 in clutch apply mode and deflects in clutch release modesimilar to seal 200 described above. Cover 510 includes circumferentialwall 512 in sealing engagement with seal 502. Wall 512 is a portion ofelement 514 fixedly attached to shell 516 at weld 518.

The following description is made with reference to FIG. 8. FIG. 8 is atop half cross-sectional view of torque converter 600 with clutchassembly 602 having deflectable seal 618, according to an exampleaspect. Assembly 602 includes piston plate 604 and seal plates 606 and608 fixed to piston plate 604 by riveting, for example. Seal 610 isdisposed between plates 606 and 608 and seals piston plate 604 to covershell 612 at circumferential surface 614.

Piston plate 604 includes orifice 616. Clutch assembly 602 includesdeflectable seal 618 fixedly attached to piston plate 604 by rivet 620.Seal 618 is arranged to restrict fluid flow through orifice 616. Thatis, during apply mode, seal 618 covers orifice 616 preventing flow offluid between chambers 622 and 624. In release mode, seal 618 deflects,allowing fluid flow between chambers 622 and 624 to cool converter 600as described supra.

The following description is made with reference to FIGS. 8-9B. FIG. 9Ais a front view of seal 618 of FIG. 8. Seal 618A includes elongated body650 with apertures 652 and 654. Length of body 650 increases flexibilityof seal 618. Rivet 620 is disposed in aperture 652. An additional rivetor protrusion (not shown) is disposed in aperture 654 to ensure seal618A is disposed over orifice 616. That is, aperture 654 is to controlcircumferential position of seal 618A relative to an axis passingthrough aperture 652. Optional friction material pad 656 may be bondedto body 650 to improve sealing performance. Although friction materialis specified, other materials may be used to improve sealing. Forexample, rubber or elastomers may be used to improve sealing.

FIG. 9B is a front view of an alternative embodiment of seal 618 of FIG.8. Seal 618B includes annular ring portion 660 with apertures 662 andradial tabs 664. Rivets 620 is disposed in apertures 662. Tabs 664 aredisposed over orifices 616. Option friction material pads 666 may bebonded to tabs 664 to improve sealing performance.

The following description is made with reference to FIGS. 10-11. FIG. 10is a cross-sectional view of a portion of clutch assembly 700, accordingto an example aspect. Clutch assembly 700 includes piston plate 702 andclutch plate 704. Sealing plate 706 is fixed to piston plate 702 by weld708. Plate 706 includes annular groove 710. Seal 712 is disposed ingroove 710, and seals plate 706 to cover assembly 714 at circumferentialsurface 716. Surface 716 is a portion of element 718 fixed to covershell 720 by weld 722. Although element 718 is shown as a separatecomponent, surface 716 may be integral with shell 720 as describedsupra. Operation of clutch assembly 700 is similar to operation ofclutch assembly 602 described supra.

FIG. 11 is a cross-sectional view of a portion of clutch assembly 800,according to an example aspect. Assembly 800 includes piston plate 802and sealing plate 804 fixed to piston plate 802 by rivet 806. Plates 802and 804 include respective circumferential walls 808 and 810, and radialwalls 812 and 814 forming portions of annular groove 816 for receiving aseal (not shown). Remaining features of clutch assembly 800 are similarto clutch assembly 700 described supra.

Of course, changes and modifications to the above examples should bereadily apparent to those having ordinary skill in the art, withoutdeparting from the spirit or scope of the invention as claimed. Althoughthe invention is described by reference to specific preferred and/orexample embodiments, it is clear that variations can be made withoutdeparting from the scope or spirit of the invention as claimed.

What we claim is:
 1. A torque converter assembly comprising: a cover fordriving engagement with a prime mover; a piston plate including anannular surface for engaging a clutch; and, a sealing plate, fixedlyattached to the piston plate, comprising a substantially radial wallarranged between the cover and the piston plate and disposed radiallyinward of the annular surface, wherein: in a lockup mode for the torqueconverter, the sealing plate blocks fluid flow between the cover and thepiston plate; and, in a release mode for the torque converter, thesealing plate is deflectable to enable a fluid flow between the coverand the piston plate via a pathway between one of the cover and thesealing plate or the sealing plate and the piston plate.
 2. The torqueconverter assembly of claim 1 wherein the sealing plate is arranged forsealing engagement with the cover.
 3. The torque converter assembly ofclaim 2 wherein the sealing plate includes a flap portion deflectableto: block the fluid flow between the cover and the piston plate; or,enable the fluid flow between the cover and the piston plate via apathway between the cover and the sealing plate.
 4. The torque converterassembly of claim 3 wherein the cover has an inner surface and wherein,during the lockup mode, the sealing plate flap is in contact with theinner surface of the cover.
 5. A torque converter assembly comprising: acover for driving engagement with a prime mover; a piston plateincluding an annular surface for engaging a clutch; and, a sealing platecomprising a substantially radial wall arranged between the cover andthe piston plate and disposed radially inward of the annular surface,wherein: in a lockup mode for the torque converter, the sealing plateblocks fluid flow between the cover and the piston plate; and, in arelease mode for the torque converter, the sealing plate is deflectableto enable a fluid flow between the cover and the piston plate via apathway between one of the cover and the sealing plate or the sealingplate and the piston plate; wherein the sealing plate comprises a sheetmetal ring fixed to one of the piston plate or the cover and arrangedfor sealing engagement with the other of the piston plate or the coverwhen the torque converter is in the lockup mode; and, wherein, duringthe lockup mode, the sheet metal ring is in contact with the other ofthe piston plate or the cover.
 6. The torque converter assembly of claim5 wherein the sealing plate further comprises a sealing portionincluding rubber or friction material bonded to the sheet metal ringand, during the lockup mode, the sealing portion is in contact with theother of the piston plate or the cover.
 7. A torque converter assemblycomprising: a cover for driving engagement with a prime mover; a pistonplate including an annular surface for engaging a clutch; and, a sealingplate comprising a substantially radial wall arranged between the coverand the piston plate and disposed radially inward of the annularsurface, wherein: in a lockup mode for the torque converter, the sealingplate blocks fluid flow between the cover and the piston plate; and, ina release mode for the torque converter, the sealing plate isdeflectable to enable a fluid flow between the cover and the pistonplate via a pathway between one of the cover and the sealing plate orthe sealing plate and the piston plate; wherein the sealing platefurther comprises: a sealing portion and friction material bonded to thesealing portion; and, in the lockup mode, the friction material blocksfluid flow between the cover and the piston plate; and, in the releasemode, the friction material is displaceable to enable fluid flow betweenthe cover and the piston plate via a pathway between one of the coverand the friction material or the friction material and the piston plate.8. A torque converter assembly comprising: a cover for drivingconnection to a prime mover; an impeller drivingly connected to thecover; a piston plate; a first chamber at least partially defined by thecover and the piston plate; a second chamber at least partially definedby the cover, the impeller, and the piston plate; and, a deflectableseal comprising a substantially radial wall arranged between the coverand the piston plate and fixed to one of the cover or the piston platefor sealing engagement with the other of the piston plate or the cover,wherein: in a first position, the deflectable seal is disengaged fromthe other of the cover or the piston plate to enable a flow around theseal from the first chamber to the second chamber; and, in a secondposition, the deflectable seal is engaged with the other of the cover orthe piston plate to block a flow from the second chamber to the firstchamber.
 9. The torque converter assembly of claim 8 further comprisinga sheet metal plate fixed to the piston plate, wherein: the deflectableseal is fixed to the sheet metal plate, arranged for sealing engagementwith the cover, and includes a flap portion deflectable to: enable theflow from the first chamber to the second chamber; or, block the flowfrom the second chamber to the first chamber.
 10. The torque converterassembly of claim 8 wherein the deflectable seal comprises a sheet metalring fixed to one of the piston plate or the cover and arranged forsealing engagement with the other of the piston plate or the cover toblock the flow from the second chamber to the first chamber.
 11. Thetorque converter assembly of claim 10 wherein the deflectable sealfurther comprises a sealing portion bonded to the sheet metal ring andcontactable with the other of the piston plate or the cover to block theflow from the second chamber to the first chamber.
 12. A torqueconverter assembly comprising: a cover for driving engagement with aprime mover and including: a shell; and, a circumferential wall; apiston plate including an annular surface for engaging a clutch; and, adeflectable seal comprising a substantially radial wall arranged betweenthe cover and the piston plate and disposed radially inward of theannular surface, wherein: in a lockup mode for the torque converter, thecircumferential wall is in sealing engagement with the seal to blockfluid flow between the cover and the piston plate; and, in a releasemode for the torque converter, the seal is deflectable to enable a fluidflow between the cover and the piston plate via a pathway between thecircumferential wall and the seal.
 13. The torque converter assembly ofclaim 12 wherein the seal includes: a first portion fixedly attached tothe piston plate; and a second portion fixed to the first portion. 14.The torque converter assembly of claim 13 wherein the second portionincludes a flap for deflecting.
 15. The torque converter assembly ofclaim 13 wherein the second portion is a rubber seal portion.
 16. Thetorque converter assembly of claim 12 where the circumferential wall isfixedly attached to the shell.
 17. The torque converter assembly ofclaim 12 wherein the seal further comprises: a sealing portion andfriction material bonded to the sealing portion; and, in the lockupmode, the friction material blocks fluid flow between the cover and thepiston plate; and, in the release mode, the friction material isdisplaceable to enable fluid flow between the cover and the piston platevia a pathway between the circumferential wall and the frictionmaterial.